Piston valve

Abstract

A piston valve for use in connection with the fire protection industry is disclosed which includes features for protecting against corrosion. A sacrificial zinc anode is mounted in the body of the valve under the handwheel. A polymeric piston is used which cannot corrode. A grease fitting protects against corrosion at the interface of the spindle and the valve body or bushing within the body.

I claim: 
     
       1. A piston valve for controlling the flow of electrolytic fluid therein comprising; a body; a sleeve; a polymeric piston movable with respect to said sleeve; a spindle for moving said piston and opening and closing said valve; said spindle including a grease fitting for lubricating said spindle and said body of said valve; a sacrificial anode mounted to said body and extending inwardly therefrom into said valve body; and, said sacrificial anode combining chemically with said electrolytic fluid such that said anode is gradually dissolved in said electrolytic fluid at a rate dependent upon the properties of said electrolytic fluid thereby protecting said body, said sleeve, and said piston from corrosion. 
     
     
       2. A piston valve as claimed in claim 1 wherein said sleeve is affixed to said body. 
     
     
       3. A piston valve as claimed in claim 2 further comprising a guide mounted in said polymeric piston for preventing rotation of said piston. 
     
     
       4. A piston valve for controlling the flow of electrolytic fluid therein comprising: a body; a sleeve affixed to said body; a polymeric piston movable with respect to said sleeve; a spindle for moving said piston and opening and closing said valve; said spindle including a grease fitting for lubricating said spindle; and, a bushing for mounting said spindle with respect to said body; a sacrificial anode mounted to said body and extending inwardly therefrom into said valve body; and, sacrificial anode combining chemically with said electrolytic fluid such that said anode is gradually dissolved in said electrolytic fluid at a rate dependent upon the properties of said electrolytic fluid thereby protecting said body, said sleeve, and said piston from corrosion. 
     
     
       5. A piston valve as claimed in claim 4 wherein said sleeve is a truncated cylinder.